CN112635179B

CN112635179B - Wireless charging device

Info

Publication number: CN112635179B
Application number: CN202011575501.4A
Authority: CN
Inventors: 李谦
Original assignee: Xi'an Dianche Fengyun Intelligent Technology Co ltd
Current assignee: Xi'an Dianche Fengyun Intelligent Technology Co ltd
Priority date: 2020-12-28
Filing date: 2020-12-28
Publication date: 2022-05-03
Anticipated expiration: 2040-12-28
Also published as: CN112635179A

Abstract

The invention discloses a wireless charging device, which comprises a transmitting coil array consisting of a plurality of groups of coils, wherein each group of coils comprises two single-turn small coils, the two single-turn small coils are centrosymmetric in structure and are respectively a 'go' coil and a 'return' coil; the 'return' coils are arranged in a line, the 'go' coils and the 'return' coils in the same column are arranged at intervals, the current flow directions of all the single-coil small coils are the same, all the single-coil small coils are connected in series to form a large coil, and one coil enters and one coil exits. The invention does not need coil superposition, greatly reduces the volume and the weight, improves the energy average degree of a single-sided magnetic field, has no obvious blind area, ensures that receiving equipment can be randomly spliced on a charging flat plate, reduces the cost, and improves the control stability, the charging efficiency and the applicability.

Description

Wireless charging device

Technical Field

The invention belongs to the technical field of inductive power transmission, and relates to a wireless charging device.

Background

The coil that current most wireless charging device adopted mainly uses QI technical standard: the coil and the magnetic core are combined to improve the transmission efficiency. In order to achieve rapid charging, the tightly wound coil is difficult to dissipate heat and is easy to generate heat, and a heat dissipation structure needs to be added, so that the problems of weight and durability exist besides cost and complexity. In the wireless charging plane board with limited volume, the more complex the splicing of the structure and the module, the more tiny structure hidden danger is represented, in addition, the application of a magnetic field, the more plastic materials are needed, the crystallization durability of the superposition type technology is poor, various fault problems are easily derived, in order to avoid the problems, the transmission power has to be reduced, the temperature is reduced on a layer invisible to a user, meanwhile, the stability is increased, and the energy is difficult to be transmitted with larger power for a long time.

Prior art 1 (patent application publication No. CN 110571031A) discloses a wireless charging transmitting coil, which includes at least two coil wiring layers stacked up and down, each coil wiring layer includes a plurality of coils disposed on the same plane; each coil in the current coil wiring layer is respectively arranged in each charging blind area of other coil wiring layers; the utilization rate of the wireless charging transmitting terminal is improved through the stacking of the multiple coils. The technical scheme needs a plurality of kHz independent coil stacking arrays with QI technical standards, the structure is complex, and a large number of charging blind areas and large density areas are still left in practical use; with two wires per coil, there are many pairs of wires in a large array, and the more coil modules, the more ports required for control, transmission and protocol processing. Thus, the hardware requirements are high and the associated system firmware can be problematic and require more time and effort to process. Then the overall central control module cost and design difficulty can be high.

Prior art 2 (patent application publication No. CN 105723479A) discloses a transmitter for an inductive power transfer system having a plurality of transmitting coils for generating an alternating magnetic field, the transmitting coils being arranged in a row by each transmitting coil partially overlapping with adjacent transmitting coils in the row, a transmitting circuit connected to each transmitting coil being capable of driving the transmitting coils so that the alternating magnetic field of each transmitting coil is phase-shifted with respect to the alternating magnetic field of adjacent transmitting coils in the row or so that the alternating magnetic field generated by the transmitting coils is translated along a charging surface. Because each transmitting coil is partially overlapped with the adjacent transmitting coils in the row, the hollow area of each transmitting coil is shielded by the adjacent transmitting coils, the magnetic field in the vertical area of each transmitting coil is greatly influenced, and an area similar to 'standing wave' with high magnetic field density and a sparse semi-blind area exist; when the transmitting coil generates an alternating magnetic field to translate along the charging surface, the magnetic fields in the vertical area and the horizontal area of the transmitting coil are difficult to align, so that the coupling power is greatly reduced. In addition, each coil needs a digital control module, and the cost and the design difficulty are increased.

Disclosure of Invention

In order to solve the above problems, the present invention provides a wireless charging device, which does not require coil superposition, greatly reduces the volume and weight, improves the energy average of a single-sided magnetic field, and has no significant blind area, so that a receiving device can be arbitrarily spliced on a charging flat plate, thereby reducing the cost, improving the control stability, the charging efficiency and the applicability, and solving the problems existing in the prior art.

The technical scheme adopted by the invention is that the wireless charging device comprises a transmitting coil array formed by a plurality of groups of coils, wherein each group of coils comprises two single-turn small coils, the two single-turn small coils are centrosymmetric in structure and respectively comprise a 'go' coil and a 'return' coil; the return coils are arranged in a line, the go coils and the return coils in the same column are arranged at intervals, the current flow directions of all the single-turn small coils are the same, all the single-turn small coils are connected in series to form a large coil, and one line is connected in and one line is connected out and is connected with a driving source.

Furthermore, the lowermost row and the uppermost row of the serial array are both 'go' coils, the outer end of the first 'go' coil of the lowermost row is electrically connected with the positive electrode of the power supply, the outer ends of the adjacent 'go' coils in the same row are electrically connected, the 'go' coil of the uppermost row is electrically connected with the outer end of the adjacent 'return' coil in the same row, the outer ends of the adjacent 'return' coils in the same row are electrically connected, the outer end of the last 'return' coil of each row along the current flow direction is electrically connected with the outer end of the adjacent 'go' coil of the lower row, and therefore, the last 'return' coil of the whole serial array along the current flow direction is electrically connected with the negative electrode of the power supply.

Further, the "go" coil and the "return" coil in the same column are aligned left and right.

Further, the shape of the single-turn small coil is approximate to a circle.

Further, the single-turn small coil is octagonal, circular, hexagonal or pentagonal.

Furthermore, the distance between the single-loop small coils is 0.3mm-1 mm.

Furthermore, the diameter of each single-turn small coil is 5mm-10 mm.

Further, all the single-turn small coils have the same structure and size.

Furthermore, all the single-turn small coils are buried in a multilayer PCB, all the single-turn small coils are arranged on the same plane, and the single-turn small coils are connected with the connecting lines of other layers through the blind holes of the PCB to form a uniform magnetic field plane.

Furthermore, a magnetic core envelope is pasted on one side of the PCB, which is far away from the receiving end, and is used as a magnetic separator.

The invention has the beneficial effects that:

the vertical area magnetic field of the transmitting coil array is far more than the transverse area magnetic field, the transmitting coil array has one line in and one line out, the transmitting coil array can be regarded as a coil, no coil superposition is needed, the size and the weight are greatly reduced, meanwhile, the average degree of the energy of the magnetic field on the single surface is high, no obvious blind area exists, the receiving end abnormity or damage caused by the over-strong magnetic field in certain areas is avoided, a plurality of receiving devices can be spliced on the charging flat plate at will, the expansion is easier, the cost is reduced, and the charging efficiency and the applicability are improved.

The invention does not use extra winding coil modules, works in one circuit board, allows near field transmission of mm grade, only needs one driving source for the transmitting coil array, reduces complexity, engineering pressure and post-manufacturing cost, and simultaneously improves stability.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic diagram of the structure of each group of coils in the embodiment of the present invention.

Fig. 2 is a partial structural schematic diagram of a transmitting coil array in the embodiment of the invention.

Fig. 3 is a schematic diagram of the overall structure of the transmitting coil array in the embodiment of the invention.

Fig. 4 is a schematic current flow diagram of the transmit coil array in an embodiment of the invention.

Fig. 5 is a simulated magnetic field of a transmit coil array in an embodiment of the invention.

Fig. 6 is a simulated magnetic field of a prior art transmitting coil.

Fig. 7 is a simulation magnetic field of a prior art transmit coil array.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The wireless charging device comprises a transmitting coil array consisting of a plurality of groups of coils, wherein each group of coils comprises two single-turn small coils, the two single-turn small coils are centrosymmetric in structure, and the two single-turn small coils are respectively a 'go' coil and a 'return' coil as shown in figure 1.

As shown in fig. 2-4, the return coils are arranged in a line, the go coils and the return coils in the same column are arranged at intervals, all the small coils in the single coil have the same current flow direction, all the small coils in the single coil are connected in series to form an array and are densely arranged to form a large coil, the current forms an S-shaped loop, and one of the two coils is connected with a driving source.

Specifically, the lowermost row and the uppermost row of the serial array are both 'go' coils, the outer end of the first 'go' coil of the lowermost row is electrically connected with the positive electrode of the power supply, the outer ends of the adjacent 'go' coils in the same row are electrically connected, the 'go' coil of the uppermost row is electrically connected with the outer end of the adjacent 'return' coil in the same row, the outer ends of the adjacent 'return' coils in the same row are electrically connected, the outer end of the last 'return' coil in each row along the current flow direction is electrically connected with the outer end of the adjacent 'go' coil in the lower row, and the length and width of the array can be infinitely increased by the circulation; the last return coil of the whole series array along the current flow direction is electrically connected with the negative pole of the power supply.

The go coil and the return coil of the invention need to be aligned left and right, thereby avoiding the magnetic field cross coupling and generating the uneven large magnetic field.

All the single-turn small coils have the same structure and size and are used for limiting the density of a magnetic field and improving the uniformity of the magnetic field; if the structures or dimensions are not identical, the magnetic field density is difficult to control and is not uniform, resulting in uneven received power.

Hundreds of single-coil small coils are arranged into a large array continuously at one time from one line to the other line, and can be considered as one coil; the entire array is buried in a multi-layer PCB, unlike Qi, where one litz wire per coil, one glue layer, one magnetic chip layer, one plastic or metal spacer layer, etc. are stacked. All the single-turn small coils are in the same plane, the more the coils are close to the outside (close to air), the lower the magnetic field loss is, part of the connecting circuits are in the next layer, and the single-turn small coils embedded in the PCB layer are connected with the copper sheet of the connecting circuits through the blind holes of the PCB to form a uniform magnetic field plane, so that a large-proportion unidirectional magnetic field is generated. When the array works in a resonant mode, all receiving coils with the same frequency on the array can receive certain near-field energy. One side of the PCB, which is far away from the receiving end, is pasted with a magnetic core envelope as a magnetic separator.

The shape of the single-turn small coil is close to a circle and can be octagonal, circular, hexagonal or pentagonal, and the generated magnetic field is easy to control; the octagonal shape is optimized, the space is fully utilized, and meanwhile, the lower layer circuit can be connected through the through hole; compared with a circular shape, the octagonal single-turn small coil is arranged more densely, if the number of the corners is too small, the second layer is covered by the through holes, and the positions cannot be found to connect the first layer.

The invention designs a single-coil series array which can present equidirectional current and magnetic field on a PCB board by using a mode of isostatically working with Taiji pattern, and the same principle as Yin and Yang is that the Yin-Yang Taiji pattern is a presentation mode of self-compensation, and is referred to as the positive and negative poles, and the 'positive pole' and 'negative pole' in the electrical science are isostatically working, namely the direction of electricity flows from 'positive' to 'negative'. According to the invention, through a smart dense arrangement mode, when the single-turn small coils which go back and forth gradually increase in the array, all the single-turn small coils generate magnetic fields in the same direction on the PCB, and the generated total magnetic field is smooth and unidirectional, rather than elliptical or circular.

The array capable of being increased and decreased integrally comprises a large coil consisting of a plurality of single-turn small coils within a specification size, and the magnetic field of the single-turn small coils is also circular. But since only a minimum number of turns is used: 1 turn, then when many of these single turns of small coils are swung very close (0.3 mm apart) (fig. 4), the simulated magnetic field is shown in fig. 5; the large-scale unidirectional magnetic field is generated, the uniform magnetic field plane is formed, the blind area is not obvious, the receiving end is prevented from being abnormal or damaged due to the fact that the magnetic field intensity of certain areas is too strong, a plurality of receiving devices can be spliced on the charging flat plate randomly, the expansion is easier, the cost is reduced, and the charging efficiency and the applicability are improved.

The distance between the single-turn small coils exceeds 0.3mm, the density of a non-right-angle magnetic field is increased, the influence is also increased, and the uneven density of the right-angle magnetic field on the front surface is caused. The diameter of each single turn of small coil ranges from 5mm to 10mm, beyond which the entire planar magnetic field is not smooth and consequently not uniform.

The existing transmitting coil is a coil module wound by many coils of wires, the coil module is in a kHz level, the magnetic field of the existing transmitting coil is as shown in fig. 6, the magnetic field generated by any power is circular/elliptical, no matter how the coil module is arrayed or driven, the total magnetic field cannot be a straight line because the magnetic field of a single module is circular, the arrayed magnetic field is as shown in fig. 7, a rectangle represents a complex coil module array, and a circle is the near-field magnetic field of each coil module, so that the existing transmitting coil cannot approach to a true one-way state like the existing transmitting coil, and the average degree of the magnetic field energy is poor.

If only 1 turn of conventional coil is arranged in a 17 × 27 array, even if the coil diameter and distance are the same as those of the embodiment of the present invention, since the wire of the conventional coil is tightly attached to the magnetic chip and has only 1 turn, it is difficult to emit magnetic field per turn, and the magnetic field is absorbed into the ferrite core according to the same principle and phenomenon as the magnetic ring inductance. In addition, each coil of the conventional coil is connected with the control module through an outgoing line, which has 17 × 27 pairs of outgoing lines, greatly increasing the cost and the design difficulty.

In the prior art 1, a plurality of stacked coils are combined to reduce blind areas, and two wires are arranged in each coil, so that a large array has a plurality of pairs of wires; prior art 2 includes multiple transmit coils, each of which needs to be driven by a corresponding transmit circuit; the

prior art

1 and 2 consisting of N coils mean that N real-time controls are needed, and the cost and the control difficulty are increased to a great extent.

Compared with the prior art, the invention has the advantages that:

1. the invention allows near field transmission of mm grade, compared with multilayer coil array, the invention has no superposition array which is thinner certainly, the volume and the weight are reduced to a great extent, and the cost is reduced; because the superposition of the coil on the PCB means doubling the PCB substrate layers, layer by layer, thickness and money; meanwhile, the magnetic field of the vertical area of the transmitting coil array is far more than that of the transverse area, and the honeycomb array formed by single lines of the octagonal Taiji diagram along with the small time circles has no superposed components, so that the magnetic field is not staggered with other coils, the magnetic field energy on the PCB is very even, the magnetic field density is uniform, the blind area is reduced to the maximum extent, and the simulated magnetic field is as shown in FIG. 5; therefore, the receiving equipment can be spliced on the charging flat plate at will, and the charging efficiency and the applicability are improved.

2. The transmitting coil array only needs one driving source, can adopt a full PCB process, has a simple structure, is designed integrally and can be very thin; because the coil is a whole, not every coil needs a drive and overlaps each other, has reduced the loss to a great extent, has reduced complexity, engineering pressure and back cost, has improved stability simultaneously. The wireless charging device only needs to adjust the resonant frequency and add a power amplifier, and can receive energy according to the resonant area as long as the resonant frequency is the same regardless of the size of a receiving end. The transmitting coil array in the embodiment can be excited to resonate with the 6.78MHz power amplifier module, and can be adjusted to other frequencies theoretically.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. A wireless charging device is characterized by comprising a transmitting coil array formed by a plurality of groups of coils, wherein each group of coils comprises two single-turn small coils, the two single-turn small coils are centrosymmetric in structure and are respectively a 'go' coil and a 'return' coil; the return coils are arranged in a line, the go coils and the return coils in the same column are arranged at intervals, the current flow directions of all the single-turn small coils are the same, all the single-turn small coils are connected in series to form a large coil, and one coil enters and one coil exits;

the bottom row and the top row of the serial array are all 'go' coils, the outer end of the first 'go' coil of the bottom row is electrically connected with the positive electrode of the power supply, the outer ends of the adjacent 'go' coils in the same row are electrically connected, the 'go' coil of the top row is electrically connected with the outer end of the adjacent 'return' coil in the same row, the outer end of the adjacent 'return' coil in the same row is electrically connected, the outer end of the last 'return' coil of each row along the current flow direction is electrically connected with the outer end of the adjacent 'go' coil of the bottom row, and therefore the last 'return' coil of the whole serial array along the current flow direction is electrically connected with the negative electrode of the power supply in a circulating mode.

2. The wireless charging device of claim 1, wherein said "go" coil and "go" coil are aligned side-to-side.

3. A wireless charging device as claimed in claim 1, wherein the shape of the single small coil is approximately circular.

4. The wireless charging device of claim 1, wherein the single-turn small coil is octagonal, circular, hexagonal or pentagonal.

5. A wireless charging device as claimed in claim 1, wherein the single small coil pitch is 0.3mm to 1 mm.

6. A wireless charging device according to claim 1, wherein each of said single small turns has a diameter of 5mm to 10 mm.

7. The wireless charging device of claim 1, wherein all of the single-turn small coils are identical in structure and size.

8. The wireless charging device of claim 1, wherein all the small single-turn coils are embedded in a multi-layer PCB, all the small single-turn coils are in a plane, and the small single-turn coils are connected with the connecting lines of other layers through the blind holes of the PCB to form a uniform magnetic field plane.

9. The wireless charging device of claim 8, wherein a magnetic core envelope is attached to a side of the PCB away from the receiving end to serve as a magnetic spacer.